Centrifugal Fan

Definition - What does Centrifugal Fan mean?

A centrifugal fan is a type of fan commonly used to power ventilation systems in environments that would otherwise have a low standing air quality either due to limited oxygen or the presence of harmful gases or particulates. These fans are sometimes called “squirrel cage fans” because they are composed of a series of overlapping blades grouped in a manner that make the fans look somewhat like hamster wheels.

Centrifugal fans work by drawing air toward the center of the fan and then discharging it at a predictable 90-degree angle from the direction of air intake. They have a relatively low cost to operate, can effectively move air within a variety of airflow conditions, and operate quietly. Because of these properties, they are commonly used to move air throughout ventilation systems, or they are oriented on top of chimneys for the purpose of driving hot, stale, or dirty air out of a workspace and ejecting it into the surrounding environment.

Safeopedia explains Centrifugal Fan

Centrifugal fans are one of two main types of fans used in fan-based ventilation systems. (Ventilation refers to the removal of contaminated air and its replacement with clean air.) The other type is the axial fan, which looks like a typical propeller. Centrifugal fans are generally preferred for situations when air needs to be pushed or pulled through a duct or tube system.

Whether a centrifugal fan is appropriate for a given workplace depends on factors such as the amount of ventilation that is required, as well as the material present in the atmosphere. Many centrifugal fans can effectively exhaust atmosphere that contains light particulates, as their rotating axle can be enclosed separately from the blades, and their directed, high-pressure airflow allows particulates to be effectively moved into a separate environment.

Centrifugal fans are often used in workplaces where ventilation is required to ensure worker safety. OSHA standard 1926.57 requires mandatory ventilation be used in situations where construction work results in atmospheric contamination to a level that exceeds OSHA exposure limits. The Air Movement Control Association’s standards for the proper setup of centrifugal fans are recognized by OSHA as providing a standards-compliant method for setting up a ventilation system.

The use of a centrifugal fan as an instrument for providing air ventilation for mine workers was first described in the 1500s; however, they first became common after the invention of the “Guibal fan” in 1859. These fans were built on top of dedicated mine shafts and reached as large as 50 feet across. Their superior ventilation power allowed mines to be built deeper than they had previously been.